Question

A rectangular strip of dimension 21cm*7cm is rolled along the longer side. Find the volume of the solid thus generated​

Answer 1

Answer: Volume of solid that generated is 81.31 cm³.

Step-by-step explanation:

Since we have given that

Length of rectangular strip = 21 cm

Width of rectangular strip = 7 cm

Since a rectangular strip is rolled along the longer side i.e. 21 cm

So, Height of cylinder becomes 21 cm

Circumference of base of cylinder = 7 cm

As we know the formula for "Circumference of circle":

C=2\pi r\\\\7=2\times\frac{22}{7}\times r\\\\\frac{7\times 7}{2\times 22}=r\\\\\frac{49}{44}=r\\\\\r=1.11\ cm

So, Volume of cylinder is given that

Volume=\pi r^2h\\\\Volume=\frac{22}{7}\times 1.11\times 1.11\times 21\\\\Volume=22\times 1.11\times 3\times 1.11\\\\Volume=81.31\ cm^3

Hence, Volume of solid that generated is 81.31 cm³.